Electric discharge tube



Nov. 22, 1949 T. HAGENBERG ELECTRIC DISCHARGE TUBE Filed NOV. 25; 1947 fig. 1.

Tzliopom/s mam/3512a.

' AGENT Patented Nov. 22, 1949 UNITED STATES PATENT OFFICE ELECTRIC DISCHARGE TUBE Application November 25, 1947, Serial No. 788,068 In the Netherlands December 7, 1946 1 Claim.

The invention relates to electric discharge tubes which contain a quantity of liquid mercury, for example an electrode, and the wall of which consists either wholly or partly of glass or similar material.

It is known that with tubes consisting wholly or partly of glass, the large quantities of mercury of one or more electrodes may damage the tube when the latter is moved.

It is also known to arrange a conical screen above the mercury cathode in such manner that when the tube is turned upside down, the mercury remains on this screen. This screen has to be provided, however, over the whole of the cross-sectional area of the tube and consequently it may have a harmful eifect on the circulation of vapour and on the discharge in the tube.

The applicant has found that, more particularly the elongated glass parts of discharge tubes, which parts are produced by sealing a smaller tube to the discharge tube, are damaged by moving quantities of mercury. For example, tubes containing at the lower end a liquid electrode, generally have at the top an exhaust tube closed, by sealing, so as to form a tip. If for some reason or other the discharge tube is turned upside down, all the mercury flows towards the exhaust tube and even when the tube is slowly turned, the weak sealing-off tip soon becomes cracked or even is entirely beaten oif.

These damages may be prevented in a simple manner by making use of the present invention.

According to the invention, in an electric discharge tube in which a quantity of liquid mercury, for example an electrode, is present and the wall of which comprises one or more elongated parts produced by sealing a smaller tube to the discharge tube, the tubes sealed to the latter are continued within the discharge tube over a length such that, when the discharge tube is turned upside down, so that the elongated part points vertically downwards, this continued tube protrudes from the quantity of mercury or remains only slightly under the surface thereof.

It is thus achieved that solely the mercury present within the protruding tube, may exert forces on the end of the latter, which has been sealed in the usual manner or which is provided with an electrode leading-in conductor sealed into it, so that, even when the tube is treated comparatively roughly, cracks are not produced at the abovementioned points.

The invention will be explained more fully with reference to the accompanying drawing wherein Fig. 1 represents a discharge tube according to the invention comprising two liquid electrodes and Fig. 2 represents the same tube with the sealed exhaust tube pointing vertically downwards. In the figures, I denotes the wall of the tube and 2 and 3 designate leading-in wires of two mercury electrodes which are separated from one another by a glass screen 4. In the right-hand electrode is provided an ignition electrode 5 constituted by a metal wire coated with glass whereas above the other electrode an auxiliary anode 6 is arranged. At the top the tube is provided with an exhaust tube 1 which is continued in the interior of the discharge tube over a length such that, when the tube is turned upside down (Fig. 2), it protrudes from the mercury 8.

What I claim is:

An electric discharge tube which contains a quantity of liquid mercury, for example an electrode, and the Wall of which comprises one or more elongated parts produced by sealing a smaller tube to the discharge tube, one or more of these additional tubes being continued in the interior of the discharge tube over a length such that, when the latter tube is turned upside down with the elongated part pointing vertically downwards, they protrude from the mercury or remain only slightly under the surface thereof.

THEODORUS HAGENBERG.

REFERENCES CITED FOREIGN PATENTS Country Date Switzerland Mar. 1, 1939 Number 

